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[PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro

Uros Bizjak posted 1 patch 1 year, 9 months ago
There is a newer version of this series
arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
[PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Uros Bizjak 1 year, 9 months ago 
Use _Q_LOCKED_VAL instead of hardcoded $0x1 in PV_UNLOCK_ASM macro.

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
---
 arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 466af57b8ed6..0a985784be9b 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
 #define PV_UNLOCK_ASM							\
 	FRAME_BEGIN							\
 	"push  %rdx\n\t"						\
-	"mov   $0x1,%eax\n\t"						\
+	"mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"		\
 	"xor   %edx,%edx\n\t"						\
 	LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"				\
 	"jne   .slowpath\n\t"						\
-- 
2.42.0
Re: [PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Boqun Feng 1 year, 9 months ago 
On Mon, Apr 22, 2024 at 05:17:35PM +0200, Uros Bizjak wrote:
> Use _Q_LOCKED_VAL instead of hardcoded $0x1 in PV_UNLOCK_ASM macro.
> 
> No functional changes intended.
> 
> Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Will Deacon <will@kernel.org>
> Cc: Waiman Long <longman@redhat.com>
> Cc: Boqun Feng <boqun.feng@gmail.com>
> ---
>  arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
> index 466af57b8ed6..0a985784be9b 100644
> --- a/arch/x86/include/asm/qspinlock_paravirt.h
> +++ b/arch/x86/include/asm/qspinlock_paravirt.h
> @@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
>  #define PV_UNLOCK_ASM							\
>  	FRAME_BEGIN							\
>  	"push  %rdx\n\t"						\
> -	"mov   $0x1,%eax\n\t"						\
> +	"mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"		\
>  	"xor   %edx,%edx\n\t"						\
>  	LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"				\
>  	"jne   .slowpath\n\t"						\

There is also a "cmp $0x1,%al" afterwards.

Regards,
Boqun

> -- 
> 2.42.0
>
Re: [PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Uros Bizjak 1 year, 9 months ago 
On Mon, Apr 22, 2024 at 9:45 PM Boqun Feng <boqun.feng@gmail.com> wrote:

> > diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
> > index 466af57b8ed6..0a985784be9b 100644
> > --- a/arch/x86/include/asm/qspinlock_paravirt.h
> > +++ b/arch/x86/include/asm/qspinlock_paravirt.h
> > @@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
> >  #define PV_UNLOCK_ASM                                                        \
> >       FRAME_BEGIN                                                     \
> >       "push  %rdx\n\t"                                                \
> > -     "mov   $0x1,%eax\n\t"                                           \
> > +     "mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"                \
> >       "xor   %edx,%edx\n\t"                                           \
> >       LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"                            \
> >       "jne   .slowpath\n\t"                                           \
>
> There is also a "cmp $0x1,%al" afterwards.

Not anymore. Please note that the patch is against -tip, where we have:

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=91095666125a666c8f20c2323b742c53165c0325

Thanks,
Uros.
Re: [PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Boqun Feng 1 year, 9 months ago 
On Mon, Apr 22, 2024 at 09:57:04PM +0200, Uros Bizjak wrote:
> On Mon, Apr 22, 2024 at 9:45 PM Boqun Feng <boqun.feng@gmail.com> wrote:
> 
> > > diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
> > > index 466af57b8ed6..0a985784be9b 100644
> > > --- a/arch/x86/include/asm/qspinlock_paravirt.h
> > > +++ b/arch/x86/include/asm/qspinlock_paravirt.h
> > > @@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
> > >  #define PV_UNLOCK_ASM                                                        \
> > >       FRAME_BEGIN                                                     \
> > >       "push  %rdx\n\t"                                                \
> > > -     "mov   $0x1,%eax\n\t"                                           \
> > > +     "mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"                \
> > >       "xor   %edx,%edx\n\t"                                           \
> > >       LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"                            \
> > >       "jne   .slowpath\n\t"                                           \
> >
> > There is also a "cmp $0x1,%al" afterwards.
> 
> Not anymore. Please note that the patch is against -tip, where we have:
> 

Oh, thanks for the information. Maybe it makes sense to mention the
patches dependency in the commit log?

Regards,
Boqun

> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=91095666125a666c8f20c2323b742c53165c0325
> 
> Thanks,
> Uros.
Re: [PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Uros Bizjak 1 year, 9 months ago 
On Mon, Apr 22, 2024 at 10:00 PM Boqun Feng <boqun.feng@gmail.com> wrote:
>
> On Mon, Apr 22, 2024 at 09:57:04PM +0200, Uros Bizjak wrote:
> > On Mon, Apr 22, 2024 at 9:45 PM Boqun Feng <boqun.feng@gmail.com> wrote:
> >
> > > > diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
> > > > index 466af57b8ed6..0a985784be9b 100644
> > > > --- a/arch/x86/include/asm/qspinlock_paravirt.h
> > > > +++ b/arch/x86/include/asm/qspinlock_paravirt.h
> > > > @@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
> > > >  #define PV_UNLOCK_ASM                                                        \
> > > >       FRAME_BEGIN                                                     \
> > > >       "push  %rdx\n\t"                                                \
> > > > -     "mov   $0x1,%eax\n\t"                                           \
> > > > +     "mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"                \
> > > >       "xor   %edx,%edx\n\t"                                           \
> > > >       LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"                            \
> > > >       "jne   .slowpath\n\t"                                           \
> > >
> > > There is also a "cmp $0x1,%al" afterwards.
> >
> > Not anymore. Please note that the patch is against -tip, where we have:
> >
>
> Oh, thanks for the information. Maybe it makes sense to mention the
> patches dependency in the commit log?

Hm, yes ... I should mention this as "[PATCH -tip]" in the subject
line to avoid confusion with this particular patch.

Thanks,
Uros.
Re: [PATCH] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by Boqun Feng 1 year, 9 months ago 
On Mon, Apr 22, 2024 at 10:12:11PM +0200, Uros Bizjak wrote:
> On Mon, Apr 22, 2024 at 10:00 PM Boqun Feng <boqun.feng@gmail.com> wrote:
> >
> > On Mon, Apr 22, 2024 at 09:57:04PM +0200, Uros Bizjak wrote:
> > > On Mon, Apr 22, 2024 at 9:45 PM Boqun Feng <boqun.feng@gmail.com> wrote:
> > >
> > > > > diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
> > > > > index 466af57b8ed6..0a985784be9b 100644
> > > > > --- a/arch/x86/include/asm/qspinlock_paravirt.h
> > > > > +++ b/arch/x86/include/asm/qspinlock_paravirt.h
> > > > > @@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
> > > > >  #define PV_UNLOCK_ASM                                                        \
> > > > >       FRAME_BEGIN                                                     \
> > > > >       "push  %rdx\n\t"                                                \
> > > > > -     "mov   $0x1,%eax\n\t"                                           \
> > > > > +     "mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"                \
> > > > >       "xor   %edx,%edx\n\t"                                           \
> > > > >       LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"                            \
> > > > >       "jne   .slowpath\n\t"                                           \
> > > >
> > > > There is also a "cmp $0x1,%al" afterwards.
> > >
> > > Not anymore. Please note that the patch is against -tip, where we have:
> > >
> >
> > Oh, thanks for the information. Maybe it makes sense to mention the
> > patches dependency in the commit log?
> 
> Hm, yes ... I should mention this as "[PATCH -tip]" in the subject
> line to avoid confusion with this particular patch.
> 

Anyway, the code looks good to me.

Acked-by: Boqun Feng <boqun.feng@gmail.com>

Regards,
Boqun

> Thanks,
> Uros.
[tip: locking/core] locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
Posted by tip-bot2 for Uros Bizjak 1 year, 9 months ago 
The following commit has been merged into the locking/core branch of tip:

Commit-ID:     532453e7aa78f3962fb4d86caf40ff81ebf62160
Gitweb:        https://git.kernel.org/tip/532453e7aa78f3962fb4d86caf40ff81ebf62160
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 22 Apr 2024 17:17:35 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 24 Apr 2024 11:48:08 +02:00

locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro

Use _Q_LOCKED_VAL instead of hardcoded $0x1 in PV_UNLOCK_ASM macro.

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240422151752.53997-1-ubizjak@gmail.com
---
 arch/x86/include/asm/qspinlock_paravirt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 466af57..0a98578 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -40,7 +40,7 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
 #define PV_UNLOCK_ASM							\
 	FRAME_BEGIN							\
 	"push  %rdx\n\t"						\
-	"mov   $0x1,%eax\n\t"						\
+	"mov   $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t"		\
 	"xor   %edx,%edx\n\t"						\
 	LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t"				\
 	"jne   .slowpath\n\t"						\

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